ABSTRACT
Across the behavioral sciences it is often observed that some people change more than others. For example, some individuals learn faster than others in their youth; some lose their cognitive capacities more quickly than others in old age. Why do individuals differ in their patterns of change? What variables predict differences in growth and decline? Questions such as these require models of change. Yet observed change may be due to fluctuations of measurement error, which necessitates models of growth that depict the true change experienced by individuals across occasions of measurement.
